Information processing device, control method, and storage medium

ABSTRACT

The information processing device  1 B includes an acquisition unit  51 A, a potential function synthesizing unit  53 A, and an objective function outputting unit  54 A. The acquisition unit  51 A acquires a task logical expression in which an objective task to be performed by a robot is expressed by a combination of a plurality of atomic tasks. The potential function synthesizing unit  53 A synthesizes atomic potential functions, each of which is a potential function corresponding to each of the atomic tasks, based on the task logical expression. The objective function output unit  54 A outputs an atomic potential function synthesized based on the task logical expression as an objective function for controlling the robot.

TECHNICAL FIELD

The present invention relates to a technical field of an informationprocessing device, a control method, and a storage medium for performingprocessing related to a task to be performed by a robot.

BACKGROUND ART

One of the path derivation methods for a robot is the technique calledthe potential method (artificial potential field method). In theartificial potential field method, when the robot is controlled to work,the objective function according to the work is designed, and the robotmoves in the direction in which the objective function decreases. PatentLiterature 1 discloses a robot which generates a route to the targetposition by generating a virtual attractive potential field for thetarget position and a virtual repulsive potential field for obstaclesand making them overlap. Further, Non-Patent Literature 1 discloses arobot model using the artificial potential field method in which theacceleration is used for the control input.

PRIOR ART DOCUMENTS Patent Literature

-   Patent Literature 1: JP 2009-288930A

Non-Patent Literature

-   Non-Patent Literature 1: N. E. Leonard and E. Fiorelli. Virtual    leaders, artificial potentials and coordinated control of groups.    Proc. of the 40th IEEE Conf. on Decision and Control, pp. 2968-2973,    2001.

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

When a robot executes a task with complicated work based on thepotential method, it becomes difficult to design an objective functionto be set. In such a case, there is an issue that only experts withadvanced knowledge can design the objective function.

In view of the above-described issue, it is therefore an example objectof the present disclosure to provide an information processing device, acontrol method and a storage medium capable of suitably outputting anobjective function when using the potential method.

Means for Solving the Problem

In one mode of the information processing device, there is provided aninformation processing device including: an acquisition unit configuredto acquire a logical expression in which an objective task to beperformed by a robot is expressed by a combination of a plurality oftasks; a potential function synthesizing unit configured to synthesizeatomic potential functions, each of which is a potential functioncorresponding to each of the tasks, based on the logical expression; andan objective function output unit configured to output a potentialfunction synthesized based on the logical expression as an objectivefunction for controlling the robot.

In one mode of the control method, there is provided a control methodexecuted by an information processing device, the control methodincluding: acquiring a logical expression in which an objective task tobe performed by a robot is expressed by a combination of a plurality oftasks; synthesizing atomic potential functions, each of which is apotential function corresponding to each of the tasks, based on thelogical expression; and outputting a potential function synthesizedbased on the logical expression as an objective function for controllingthe robot.

In one mode of the storage medium, there is provided a storage mediumstoring a program executed by a computer, the program causing thecomputer to function as: an acquisition unit configured to acquire alogical expression in which an objective task to be performed by a robotis expressed by a combination of a plurality of tasks; a potentialfunction synthesizing unit configured to synthesize atomic potentialfunctions, each of which is a potential function corresponding to eachof the tasks, based on the logical expression; and an objective functionoutput unit configured to output a potential function synthesized basedon the logical expression as an objective function for controlling therobot.

Effect of the Invention

An example advantage according to the present invention is to suitablydetermine and output an objective function when the potential method isused.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the configuration of a robot control system.

FIG. 2 illustrates the hardware configuration of an informationprocessing device.

FIG. 3A is an example of the data structure of an atomic task DB

FIG. 3B is an example of the data structure of atomic task information.

FIG. 4 is an example of a functional block of the information processingdevice.

FIG. 5 is an example of a task input view displayed by a display device.

FIG. 6 is an example of a flowchart executed by the informationprocessing device according to a first example embodiment.

FIG. 7 is a display example of a task input view according to amodification.

FIG. 8 is an example of a functional block of the information processingdevice which transmits a control signal indicating a control inputaccording to the modification.

FIG. 9 is a functional block diagram of an information processing deviceaccording to a second example embodiment.

DESCRIPTION OF EXAMPLE EMBODIMENTS

Hereinafter, example embodiments of an information processing device, acontrol method, and a storage medium will be described with reference tothe drawings.

First Example Embodiment

[System Configuration]

FIG. 1 shows a configuration of a robot control system 100 according tothe first example embodiment. The robot control system 100 mainlyincludes an information processing device 1, an input device 2, adisplay device 3, a storage device 4, a communication device 5, and aplurality of robots 6 (6A, 6B, . . . ). The storage device 4 includes anatomic task DB 41.

The information processing device 1 sets an objective function forcontrolling the robots 6 subjected to control according to the potentialmethod (artificial potential field approach). In this case, theinformation processing device 1 suitably generates the objectivefunction necessary for executing a task when a logical expression (alsoreferred to as “task logical expression”) which expresses a task to beperformed by the robots 6 by a combination of simple tasks is giventhrough user input. Hereafter, a task to be performed by the robots 6 isreferred to as “objective task”, and each simple task when the targettask is expressed by a combination of simple tasks is referred to as“atomic task”. The objective task is, for example, a complex task thatcauses multiple robots 6 to work jointly, and the atomic task is asimple task to be performed by one robot 6.

The information processing device 1 is electrically connected to theinput device 2, the display device 3, the storage device 4 and thecommunication device 5. For example, the information processing device 1receives the input signal “S1” generated based on the user's operationor the like from the input device 2. Here, when the input signal S1includes information indicative of the task logical expression, theinformation processing device 1 refers to the atomic task DB 41 storedin the storage device 4 and converts the task logical expressionindicated by the input signal S1 into an objective function. Further,when the input signal S1 includes information relating to updating ofthe atomic task DB 41, the information processing device 1 updates theatomic task DB 41 stored in the storage device 4 based on the inputsignal S1. Further, the information processing device 1 transmits to thedisplay device 3 a display signal “S2” for displaying informationrelating to the task to be executed by the robots 6. Further, theinformation processing device 1 transmits, to the robots 6, a controlsignal “S3” relating to the control of the robots 6 via thecommunication device 5. For example, the information processing device 1transmits, to the robots 6 through the communication device 5, thecontrol signal S3 indicative of the objective function for defining theoperation of each of the robots 6.

The input device 2 is an interface that receives the input by the usersuch as a touch panel, a button, a keyboard, a voice input device, andthe like. The input device 2 supplies the input signal S1 generatedbased on the input by the user to the information processing device 1.It is noted that the input device 2 may be integrated with theinformation processing device 1 as one device in such a state that it isincorporated in the information processing device 1.

The display device 3 displays information based on the display signal S2supplied from the information processing device 1, and the examples ofthe display device 3 include a display and a projector. As will bedescribed later, for example, on the basis of the display signal S2, thedisplay device 3 displays an input view (also referred to as a “taskinput view”) in which an objective task is to be specified in the formof a task logical expression. The display device 3 may be configured tobe integrated with the information processing device 1 as one device.

The storage device 4 is a memory configured to store the atomic task DB41 and the like. The atomic task DB 41 is a database on atomic tasksthat configure the objective tasks to be performed by the robots 6. Thedata structure of the atomic task DB 41 will be described later. Thestorage device 4 may be an external storage device such as a hard diskconnected to or built in to the information processing device 1, or maybe a storage medium such as a flash memory. The storage device 4 may bea server device that performs data communication with the informationprocessing device 1. In this case, the storage device 4 may beconfigured by a plurality of server devices.

The communication device 5 is a network adapter or the like, andcommunicates with the information processing device 1 and the robots 6.The communication between the communication device 5 and each of therobots 6 may be a wireless communication or a wired communication. It isnoted that the communication device 5 may be integrated with theinformation processing device 1 as one device in such a state that it isincorporated in the information processing device 1.

The robots 6 (6A, 6B, . . . ) perform operations based on the controlsignal S3 transmitted from the communication device 5. In the presentexample embodiment, when the objective function is specified by thecontrol signal S3, each of the robots 6 autonomously moves so that theobjective function is reduced. Further, for example, each of the robots6 acquires the respective position information regarding the own andother robots 6 in order to input to the objective function specified bythe control signal S3. In this case, each of the robots 6 includes, forexample, one or more inner-field sensors and outer-field sensors andacquires position information and the like regarding the own and otherrobots 6 based on the output of these sensors. In another example, eachof the robots 6 may acquire the position information by communicatingwith the other robots 6. In still another example, when the informationprocessing device 1 collects the position information regarding each ofthe robots 6, each of the robots 6 may receive the collected positioninformation regarding each object from the information processing device1. In still another example, when such an objective function for theobjective task that the robots 6 capture (track) one or more objects isgiven, the robots 6 acquires not only the position information regardingeach of the robots 6 but also the position information regarding theobjects.

[Hardware Configuration of Information Processing Device]

FIG. 2 shows the hardware configuration of the information processingdevice 1. The information processing device 1 includes a processor 11, amemory 12, and an interface 13 as hardware. The processor 11, the memory12, and the interface 13 are connected to one another via a data bus 19.

The processor 11 executes a predetermined process by executing a programstored in the memory 12. The processor 11 is a processor such as a CPU(Central Processing Unit) or a GPU (Graphics Processing Unit).

The memory 12 is configured by various memories such as a RAM (RandomAccess Memory) and a ROM (Read Only Memory). In addition, a program forexecuting a predetermined process by the information processing device 1is stored in the memory 12. The memory 12 is used as a work memory andtemporarily stores information acquired from the storage device 4. Thememory 12 may function as a storage device 4. Similarly, the storagedevice 4 may function as a memory 12 of the information processingdevice 1. The program executed by the information processing device 1may be stored in a storage medium other than the memory 12.

The interface 13 is an interface for electrically connecting theinformation processing device 1 and other devices. For example, theinterface 13 includes an interface for connecting the informationprocessing device 1 and the input device 2, an interface for connectingthe information processing device 1 and the display device 3, aninterface for connecting the information processing device 1 and thestorage device 4, and an interface for connecting the informationprocessing device 1 and the communication device 5. The interface forconnecting the information processing device 1 and the storage device 4may be a communication interface for wired or wireless transmission andreception of data to and from the storage device 4 under the control ofthe processor 11. In this case, the interface 13 may perform datacommunication with the storage device 4 through the communication device5. In another example, the information processing device 1 and thestorage device 4 may be connected by a cable or the like. In this case,the interface 13 includes an interface which confirms to USB or SATA(Serial AT Attachment) or the like for exchanging data with the storagedevice 4. The interface 13 may be an interface for the informationprocessing device 1 to transmit and receive signals to and from theinner sensors and the outer sensors. In this case, the external sensorsmay be a camera and/or a range measuring sensor for acquiring theposition information regarding each of the robots 6 (including theposition information regarding an object when the object is a trackingtarget).

The hardware configuration of the information processing device 1 is notlimited to the configuration shown in FIG. 2. For example, theinformation processing device 1 may include at least one of an inputdevice 2, a display device 3, a storage device 4, and a communicationdevice 5. Further, a sound output device such as a speaker may beconnected or built in to the information processing device 1. In thesecases, the information processing device 1 may be a tablet type terminalor the like in which the input function and the output function areintegrated with the main body.

[Atomic Task DB]

Next, the data structure of the atomic task DB 41 will be described.

FIG. 3A shows an exemplary data structure of the atomic task DB 41. Asshown in FIG. 3A, the atomic task DB 41 has N (N is an integer of 2 ormore) pieces of atomic task information (the first atomic taskinformation to the Nth atomic task information) corresponding to Natomic tasks, respectively. The atomic task information is informationregarding atomic tasks, and the detail thereof will be described later.The atomic task information included in the atomic task DB 41 may bestored in the storage device 4 in advance as an initial setting, or maybe generated by the information processing device 1 in response to aninput signal S1 based on a user input to the input device 2 and storedin the storage device 4.

FIG. 3B shows an example of the data structure of the atomic taskinformation (first atomic task information to N_(th) atomic taskinformation). As shown in FIG. 3B, the atomic task information mainlyincludes explanatory information, symbol information, and potentialfunction information, respectively.

The explanatory information is text information describing the contentof each atomic task. The explanatory information is used on the taskinput view to display descriptive text to describe the contents of eachatomic task that can be used to specify the task logical expression.

The symbol information indicates the symbol of each atomic task. Theabove symbol denotes the proposition (also referred to as “atomicproposition”) of each atomic task to be used in the task logicalexpression specified by the user. In other words, symbols indicated bythe symbol information are symbols indicating the propositions of theatomic tasks that can be used when the user specifies on the task inputview the task logical expression that is the combination of the atomictasks. Each atomic proposition is a proposition which becomes “1” whenthe corresponding atomic task is achieved and which becomes “0” when thecorresponding atomic task is not achieved.

The potential function information indicates a potential function(referred to as “atomic potential function”) corresponding to eachatomic task. The atomic potential function is a function that is set to“0” when a corresponding atomic task is accomplished, and set to a valuegreater than 0 otherwise. It is noted that the objective functionsupplied to each of the robots 6 by the information processing device 1through the control signal S3 corresponds to a function obtained bysynthesizing atomic potential functions according to the task logicalexpression.

As described above, each atomic task information (the first atomic taskinformation to the N_(th) atomic task information) registered in theatomic task DB 41 becomes information in which the description of eachatomic task and the symbol of the atomic proposition indicative of theeach atomic task are associated with the atomic potential functioncorresponding to the atomic proposition.

[Functional Block]

FIG. 4 is an example of a functional block of the information processingdevice 1. The processor 11 of the information processing device 1functionally includes a display control unit 50, an acquisition unit 51,an atomic task setting unit 52, a potential function synthesizing unit53, and an objective function output unit 54.

The display control unit 50 refers to the atomic task DB 41 andgenerates a display signal S2 for displaying the task input view. Then,the display control unit 50 supplies the generated display signal S2 tothe display device 3. Further, the display control unit 50 generates adisplay signal S2 for displaying a view which accepts an input relatingto the updating of the atomic task DB 41, and supplies the displaysignal S2 to the display device 3.

When the task logical expression is inputted on the task input view, theacquisition unit 51 receives an input signal S1 indicating the tasklogical expression from the input device 2. Then, the acquisition unit51 supplies the input signal S1 indicating the task logical expressionto the potential function synthesizing unit 53. Further, when receivingthe input signal S1 relating to updating of the atomic task DB 41 fromthe input device 2, the acquisition unit 51 supplies the input signal S1to the atomic task setting unit 52.

The atomic task setting unit 52 updates the atomic task DB 41 whenreceiving the input signal S1 relating to the update of the atomic taskDB 41 from the acquisition unit 51. In this case, for example, the inputsignal S1 is information indicating addition, change, or deletion of theatomic task information in the atomic task DB 41, and the atomic tasksetting unit 52 performs addition, change, or deletion of the atomictask information in the atomic task DB 41 based on the input signal S1.It is noted that the input signal S1 indicating the addition of theatomic task information includes the explanatory text of an atomic task,the symbol indicating the corresponding atomic proposition, and theinformation indicative of the corresponding atomic potential function,respectively, and that the atomic task setting unit 52 generates theatomic task information having such a data structure shown in FIG. 3Bbased on the above-mentioned information. In this case, the atomic tasksetting unit 52 registers the generated atomic task information in theatomic task DB 41.

When receiving the input signal S1 indicating the task logicalexpression from the acquisition unit 51, the potential functionsynthesizing unit 53 calculates the potential function, in which theatomic potential functions of atomic tasks used in the task logicalexpression are synthesized based on the task logical expression, withreference to the atomic task DB 41. Then, the potential functionsynthesizing unit 53 supplies the synthesized potential function to theobjective function output unit 54. Details of the processing of thepotential function synthesizing unit 53 will be described later.

The objective function output unit 54 determines the objective functionfor controlling each of the robots 6 to be the potential functionoutputted by the potential function synthesizing unit 53 as, andtransmits the control signal S3 indicating the objective function toeach of the robots 6 via the communication device 5.

Each of the robots 6 which has received the control signal S3 performsan operation based on the objective function indicated by the controlsignal S3. For example, when performing the objective task of jointlycapturing one or more objects, each of the robots 6 acquires theposition information regarding the objects and the position informationregarding each of the robot 6, and determines, on the basis of theobjective function indicated by the control signal S3, the control inputin the x-direction and y-direction defined on the horizontal plane. Inthis case, on the basis of the artificial potential field method, eachof the robot 6 determines the control input described above so as tomove in the direction in which the potential function, which is theobjective function, is lowered. Specific examples of the control inputwill be described later.

Next, a description will be given of the details of the process whichthe potential function synthesizing unit 53 executes. The potentialfunction synthesizing unit 53 executes a process (also referred to as“first conversion process”) of converting atomic propositions in thetask logical expression into atomic potential functions, and a process(also referred to as a “second conversion process”) of convertinglogical connectors in the task logical expression into operatorsapplicable to atomic potential functions, respectively.

First, a description will be given of the first conversion process. Inthe first transformation process, first, the potential functionsynthesizing unit 53 extracts atomic task information including symbolinformation indicative of symbols of atomic propositions in the tasklogical expression from the atomic task DB 41. Then, the potentialfunction synthesizing unit 53 replaces the atomic propositions in thetask logical expression by atomic potential functions indicated by thepotential function information included in the extracted atomic taskinformation.

Next, a description will be given second conversion process. In thesecond conversion process, the potential function synthesizing unit 53converts the logical connectors in the task logical expression into theabove-described operators by referring to the correspondence informationin which each logical connector is associated in advance with thecorresponding operator to be applied to the potential function. Thecorrespondence information is stored in the memory 12 or the storagedevice 4 in advance.

For example, the potential function synthesizing unit 53 converts thelogical connector “∧” indicating the logical AND (logical conjunction)into an addition operator or a maximum value operator. Further, thepotential function synthesizing unit 53 converts the logical connector“∨” indicating the logical OR (logical disjunction) into amultiplication operator or a minimum value operator.

For example, it is hereinafter assumed that the atomic proposition foratomic task “A” is denoted by “φ_(A)” and its atomic potential functionis denoted by “P_(A)(x)”, and that the atomic proposition for atomictask “B” is denoted by “φ_(B)” and its atomic potential function isdenoted by “P_(B)(x)”. Here, “x” indicates a variable vector indicatingthe position and the like of each of the robots 6.

In this case, the potential function synthesizing unit 53 converts thelogical expression “φ_(A)∧φ_(B)” that means “achieving the atomic task Aand the atomic task B” according to either of the following expressions(1) or (2).

$\begin{matrix}\left. {\varphi_{A} ⩓ \varphi_{B}}\Rightarrow{{P_{A}(x)} + {P_{B}(x)}} \right. & (1) \\\left. {\varphi_{A} ⩓ \varphi_{B}}\Rightarrow{\max\left\{ {{P_{A}(x)},{P_{B}(x)}} \right\}} \right. & (2)\end{matrix}$

According to the expression (1) or the expression (2), when both theatomic task A and the atomic task B are achieved (i.e., when the logicalexpression on the left side is true), the right side of the combinationof the atomic potential function P_(A) (x) and the atomic potentialfunction P_(B) (x) is 0, which is the smallest value.

The potential function synthesizing unit 53 converts the task logicalexpression “φ_(A) ∨φ_(B)” that means “achieving the atomic task A or theatomic task B” according to either of the following expressions (3) or(4).

$\begin{matrix}\left. {\varphi_{A} ⩔ \varphi_{B}}\Rightarrow{{P_{A}(x)} \cdot {P_{B}(x)}} \right. & (1) \\\left. {\varphi_{A} ⩔ \varphi_{B}}\Rightarrow{\min\left\{ {{P_{A}(x)},{P_{B}(x)}} \right\}} \right. & (2)\end{matrix}$

According to the expression (3) or the expression (4), when either theatomic task A or the atomic task B is achieved (i.e., when the logicalexpression on the left side is true), the right side of the combinationof the atomic potential function P_(A) (x) and the atomic potentialfunction P_(B) (x) is 0, which is the smallest value.

Hereinafter, the task logical expression “(φ_(A) ∧φ_(B))∨φ_(c)” whichmeans “the task A and the task B are accomplished, or the task C isaccomplished” is considered, wherein the atomic proposition for atomictask “C” is denoted by “φ_(C)” and its atomic potential function isdenoted by “P_(C)(x)”.

In this case, in the first example, the potential function synthesizingunit 53 converts the task logical expression “(φ_(A)∧φ_(B))∨φ_(C)” usingthe addition operator and the multiplication operator according to theexpressions (1) and (3) as shown in the following expression (5).

$\begin{matrix}\left. {\left( {\varphi_{A} ⩓ \varphi_{B}} \right) ⩔ \varphi_{C}}\Rightarrow{\left( {{P_{A}(x)} + {P_{B}(x)}} \right) \cdot {P_{C}(x)}} \right. & (5)\end{matrix}$

In the second example, the potential function synthesizing unit 53converts the task logical expression “(φ_(A)∧φ_(B))∨φ_(C)” using themaximum value operator and the minimum value operator according to theexpressions (2) and (4) as shown in the following expression (6).

$\begin{matrix}\left. {\left( {\varphi_{A} ⩓ \varphi_{B}} \right) ⩔ \varphi_{C}}\Rightarrow{\min\left\{ {{\max\left\{ {{P_{A}(x)},{P_{B}(x)}} \right\}},{P_{C}(x)}} \right\}} \right. & (6)\end{matrix}$

It is noted that the potential function synthesizing unit 53 may convertthe task logical expression according to either the combination of theexpression (1) and the expression (4) or the combination of theexpression (2) and the expression (3) instead of the conversionaccording to the expression (5) or the expression (6).

Instead of the conversion of the logical connector in the task logicalexpression according to the expressions (1) to (4), for example, thepotential function synthesizing unit 53 may convert the logicalconnector in the task logical expression according to the followingexpression (4.5).

$\begin{matrix}{{M(x)} = \left\{ \begin{matrix}0 & \left( {{p < 0} ⩓ \left( {{P_{A}(x)} = {{0 ⩔ {P_{B}(x)}} = 0}} \right)} \right. \\\left( {{P_{A}^{p}(x)} + {P_{B}^{p}(x)}} \right)^{\frac{1}{p}} & {OTHER}\end{matrix} \right.} & (4.5)\end{matrix}$

“M(x)” corresponds to both transformations of the logical expressions“φ_(A)∧φ_(B)” and “φ_(A) ∨φ_(B)”, and “p” denotes a parameter. The tasklogical expression “φ_(A)∨φ_(B)” can be converted into the expression(4.5) in case of “p<0”, and the task logical expression “φ_(A)∧φ_(B)”can be converted into the expression (4.5) in case of “p>0”. Therefore,the potential function synthesizing unit 53 sets the parameter p to“p>0” when applying the conversion shown in the expression (4.5) to thelogical expression “φ_(A)∧φ_(B)”, and sets the parameter p to “p<0” whenapplying the conversion shown in the expression (4.5) to the logicalexpression “φ_(A)∨φ_(B)”.

A further consideration will be given of the expression (4.5). When“p=1” is set, the conversion of the logical expression “φ_(A)∧φ_(B)”including the logical AND according to the expression (4.5) matches theexpression (1). When “p=co” is set, the conversion of the logicalexpression “φ_(A)∧φ_(B)” including the logical AND according to theexpression (4.5) matches the expression (2). If “p>0” is set and boththe atomic task A and the atomic task B are achieved, M(x) for thelogical expression φ_(A)∧φ_(B) is 0, which is the smallest.

On the other hand, when “p=−∞” is set, the conversion of the logicalexpression “φ_(A)∨φ_(B)” including the logical OR according to theexpression (4.5) matches the expression (4). When “p=−1” is set, theconversion of the logical expression “φ_(A)∨φ_(B)” including the logicalOR according to the expression (4.5) is expressed by the followingexpression.

$\phi_{A} ⩔ \left. \phi_{B}\Longrightarrow\frac{{P_{A}(x)} \cdot {P_{B}(x)}}{{P_{A}(x)} + {P_{B}(x)}} \right.$

If the denominator of the above expression is ignored, thistransformation is consistent with the expression (3). In the case of“p<0”, when either the atomic task A or the atomic task B is achieved,M(x) for the logical expression “φ_(A) ∨φ_(B)” is 0, which is thesmallest.

In this way, by using the above-described expressions (1) to (4) or(4.5), the potential function synthesizing unit 53 can appropriately setan objective function for controlling each of the robots 6 by convertingan arbitrary task logical expression specified by the user into anarithmetic expression of the atomic potential function. It is noted thatthe task logical expression may include a logical connector other thanthe logical AND or the logical OR such as an exclusive OR. Even in thiscase, for example, the potential function synthesizing unit 53 convertsthe exclusive OR the like into the combination of the logical AND, thelogical OR, and the logical negation and thereafter performs theabove-mentioned second conversion process. For an atomic propositionwith the logical negation, for example, the potential functionsynthesizing unit 53 converts the atomic potential functioncorresponding to the atomic proposition into the inverse thereof

Specific Example

Next, a specific example of processing based on the functional block ofthe information processing device 1 shown in FIG. 4 will be described.

FIG. 5 is an example of a task input view displayed by the displaydevice 3. In this case, for example, the display control unit 50 of theinformation processing device 1 generates the display signal S2 fordisplaying the task input view shown in FIG. 5 when the acquisition unit51 acquires the input signal S1 indicating the display request of thetask input view from the input device 2, and transmits the displaysignal S2 to the display device 3. Then, in the example of FIG. 5, thedisplay control unit 50 displays on the task input view an atomic taskexplanation area 60, a task logical expression input field 61, inputbuttons 62, and an execution button 63.

The atomic task description area 60 is an area that describes the atomictasks to be performed by the robots 6. The display control unit 50displays explanatory sentences relating to the contents of the fouratomic tasks (the first atomic task to the fourth atomic task) inassociation with the corresponding symbols (atomic propositions) on thebasis of explanatory information and symbol information respectivelyincluded in the four pieces of the atomic task information recorded inthe atomic task DB 41. Thus, the viewer of the task input view canappropriately grasp the correspondence relationship between the contentsof the first atomic task to the fourth atomic task and their symbols(atomic propositions) to be used for inputting the task logicalexpression.

The task logical expression input field 61 is an input field of the tasklogical expression, and the input buttons 62 are buttons for inputtingatomic propositions, logical connectors, and other symbols in the tasklogical expression input field 61. The display control unit 50 displays,as the input buttons 62, buttons corresponding to “φ(A, C)”, “φ(A, D)”,“φ(B, C)”, “φ(B, D)” each of which is a symbol (atomic proposition)corresponding to each of the first atomic task to the fourth atomictask, and buttons corresponding to logical connectors. Thus, the viewercan suitably specify the task logical expression for instructing thecomplex task that is a combination of the atomic tasks. Instead of theinput operation by selecting the buttons in the task logic input field61, the viewer may input the task logical expression by other operationssuch as keyboard operation or voice operation.

When detecting that the execution button 63 has been selected, theacquisition unit 51 supplies the information regarding the task logicalexpression inputted in the task logical expression input field 61 to thepotential function synthesizing unit 53. In the task input view shown inFIG. 5, the task logical expression shown in the following expression(7) is inputted in the task logical expression input field 61.

$\begin{matrix}{\left( {{\varphi\left( {A,C} \right)} ⩓ {\varphi\left( {B,D} \right)}} \right) ⩔ \left( {{\varphi\left( {A,D} \right)} ⩓ {\varphi\left( {B,C} \right)}} \right)} & (7)\end{matrix}$

In this case, with reference to the atomic task DB 41, the potentialfunction synthesizing unit 53 synthesizes the atomic potential functionsby performing the first conversion process and the second conversionprocess on the task logical expression inputted to the task logicalexpression input field 61.

Here, a description will be given of the first conversion processaccording to the expression (7). Given that “p_(a)” denotes thecoordinates of the robot A, “p_(b)” denotes the coordinates of the robotB, “p_(c)” denotes the coordinates of the moving object C, and “p_(d)”denotes the coordinates of the moving object D, the atomic proposition φ(A, C) corresponding to the first atomic task is converted, for example,to the atomic potential function “P_((A, C)) (p_(a))” corresponding tothe square of the distance between the robot A and the moving object C,as shown in the following expression (8).

$\begin{matrix}{\left. {\varphi\left( {A,C} \right)}\Rightarrow{P_{({A,C})}\left( p_{a} \right)} \right. = {{p_{c} - p_{a}}}^{2}} & (8)\end{matrix}$

The atomic propositions φ(B, D), φ (A, D), and φ (B, C) corresponding tothe second atomic task to the fourth atomic task are similarly convertedto the atomic potential functions “P_((B, D)) (p_(b))”, “P_((A, D))(p_(a))”, “P_((B, C))(p_(b))” shown in the following expressions (9) to(11), respectively.

$\begin{matrix}{\left. {\varphi\left( {B,D} \right)}\Rightarrow{P_{({B,D})}\left( p_{b} \right)} \right. = {{p_{d} - p_{b}}}^{2}} & (9) \\{\left. {\varphi\left( {A,D} \right)}\Rightarrow{P_{({A,D})}\left( p_{b} \right)} \right. = {{p_{d} - p_{a}}}^{2}} & (10) \\{\left. {\varphi\left( {B,C} \right)}\Rightarrow{P_{({B,C})}\left( p_{b} \right)} \right. = {{p_{c} - p_{b}}}^{2}} & (11)\end{matrix}$

It is noted that the atomic potential functions “P_((A, C)) (p_(a))”,“P_((B, D)) (p_(b))”, “P_((A, D)) (p_(a))”, “P_((B, C)) (p_(b))” arerecorded in the atomic task DB 41 as the potential function informationincluded in the atomic task information corresponding to the firstatomic task to the fourth atomic task.

Further, the potential function synthesizing unit 53 calculates theobjective function “P (p_(a), p_(b))”, which is a combination of atomicpotential functions, by further performing the second conversion processfor each logical connector in the expression (7). Specifically, thepotential function synthesizing unit 53 calculates the objectivefunction shown in the following expression (12).

$\begin{matrix}{{P\left( {p_{a},p_{b}} \right)} = {\left( {{P_{({A,C})}\left( p_{a} \right)} + {P_{({B,D})}\left( p_{d} \right)}} \right) \cdot \left( {{P_{({A,D})}\left( p_{a} \right)} + {P_{({B,C})}\left( p_{b} \right)}} \right)}} & (12)\end{matrix}$

Then, the objective function output unit 54 transmits the control signalS3 indicating the objective function shown in the expression (12) toeach of the robots 6 via the communication device 5. Then, the robot Aand the robot B autonomously move based on the objective functionspecified by the control signal S3 and the most recently updatedcoordinates p_(a), p_(b), p_(c), p_(d).

For example, a description will be given of the case where each of therobots 6 can freely determine the own velocity through the controlinput. In this case, when the control input for the robot A is set to“u_(a)” and the control input for the robot B is set to “u_(b)”, thederivative (i.e., movement velocity) of the position of the robot A andthe robot B is determined by the control inputs u_(a) and u_(b) as shownin the following expressions (13) and (14).

$\begin{matrix}{\overset{.}{p_{a}} = u_{a}} & (13) \\{\overset{.}{p_{b}} = u_{b}} & (14)\end{matrix}$

Here, each of the control inputs u_(a) and u_(b) is set to the partialdifferential (i.e., an artificial force field corresponding to thegradient of the potential function) of the objective function P (p_(a),P_(b)) shown in the expression (12). Specifically, the control inputsu_(a) and u_(b) are determined based on the following expressions (15)and (16).

$\begin{matrix}{u_{a} = {{- \frac{\partial P}{\partial p_{a}}}\left( {p_{a},p_{b}} \right)}} & (15) \\{u_{b} = {{- \frac{\partial P}{\partial p_{b}}}\left( {p_{a},p_{b}} \right)}} & (16)\end{matrix}$

In this way, the robot A and the robot B can move so that the objectivefunction P (p_(a), p_(b)) is reduced, and the objective task specifiedthrough the task logical expression can be preferably executed.

[Processing Flow]

FIG. 6 is an example of a flow chart in which the information processingdevice 1 according to the first example embodiment executes. Theinformation processing device 1 repeatedly executes the processing ofthe flowchart shown in FIG. 6.

First, the atomic task setting unit 52 of the information processingdevice 1 determines whether or not there is a request for updating theatomic task DB 41 (Step S11). In this case, for example, the atomic tasksetting unit 52 determines whether or not the acquisition unit 51 hasreceived from the input device 2 an input signal S1 indicating a userinput relating to addition, change, or deletion of the atomic taskinformation which is recorded in the atomic task DB 41. When there is arequest for updating the atomic task DB 41 (Step S11; Yes), the atomictask setting unit 52 updates the atomic task DB 41 based on the inputsignal S1 supplied from the input device 2 (Step S12). In this case, theatomic task setting unit 52 performs the addition, the change, or thedelete operation on the atomic task information which is recorded in theatomic task DB 41. On the other hand, when there is no request forupdating the atomic task DB 41 (Step S11; No), the informationprocessing device 1 advances the processing to Step S13.

Next, the display control unit 50 of the information processing device 1determines whether or not there is a display request of the task inputview (Step S13). In this case, the display control unit 50 determineswhether or not the acquisition unit 51 has received from the inputdevice 2 an input signal S1 indicating a user input to request a displayof the task input view, for example. When it is determined that there isa display request of the task input view (Step S13; Yes), the displaycontrol unit 50 generates the display signal S2 relating to the taskinput view and supplies the display signal S2 to the display device 3,thereby causing the display device 3 to display the task input view(Step S14). In this case, the acquisition unit 51 accepts the input ofthe task logical expression on the task input view. On the other hand,when it is determined that there is no display request of the task inputview (Step S13; No), the information processing device 1 returns theprocessing to Step S11.

Next, the acquisition unit 51 determines whether or not the input of thetask logical expression on the task input view has been completed (StepS15). When the input of the task logical expression on the task inputview has not been completed (Step S15: No), the acquisition unit 51continuously accepts the input of the task logical expression on thetask input view at Step S14.

On the other hand, when the input of the task logical expression on thetask input view has been completed (Step S15; Yes), the potentialfunction synthesizing unit 53 of the information processing device 1refers to the atomic task DB 41 and synthesizes the potential functions(Step S16). In this case, the potential function synthesizing unit 53performs a first conversion process of converting the atomicpropositions included in the input task logical expression into atomicpotential functions, and a second conversion process of converting thelogical connectors included in the input task logical expression intoarithmetic operators applicable to the atomic potential functions.

Then, the objective function output unit 54 of the informationprocessing device 1 outputs the potential function synthesized by thepotential function synthesizing unit 53 at Step S16 as an objectivefunction (Step S17). For example, the objective function output unit 54transmits a control signal S3 indicating the above-described objectivefunction to each of the robots 6 via the communication device 5.

In this way, the information processing device 1 automatically designsthe objective function for executing the objective task based on theartificial potential field method from the task logical expressionrepresented by the combination of the propositions of the atomic tasksand the logical connectors. This makes it possible for the user toeasily design the objective function in accordance with the contents ofa complicated work, which had not been able to be designed until nowwithout specialists.

[Modification]

The following modifications may be applied to the example embodimentsdescribed above in arbitrary combination.

(First Modification)

The information processing device 1 may determine the objective functionin consideration of the priority set for each atomic task.

For example, it is assumed that the degree of the priority of the task Acorresponding to the atomic proposition “φ_(A)” is “α” and the degree ofthe priority of the task B corresponding to the atomic proposition“φ_(B)” is “β”, respectively. The degrees of the priorities a and 13shall be equal to or greater than 0, respectively, and the larger thedegree thereof, the higher the priority becomes. In this case, insteadof using the expression (1), the potential function synthesizing unit 53converts the logical expression “φ_(A)∧φ_(B)” related to the logical ANDbased on the following expression (17).

$\begin{matrix}\left. {\varphi_{A} ⩓ \varphi_{B}}\Rightarrow{{\alpha \cdot {P_{A}(x)}} + {\beta \cdot {P_{B}(x)}}} \right. & (17)\end{matrix}$

In this way, the potential function synthesizing unit 53 multiplies eachatomic potential function by the degree of the priority of thecorresponding atomic task when converting the logical AND into anaddition operator. This allows the potential function synthesizing unit53 to weight each atomic potential function in accordance with thepriority and facilitate early execution of higher priority atomic tasks.

Further, the potential function synthesizing unit 53, instead of usingthe expression (3), converts the logical expression “φ_(A) ∨φ_(B)”corresponding to the logical OR based on the following expression (18).

$\begin{matrix}\left. {\varphi_{A} ⩔ \varphi_{B}}\Rightarrow{{P_{A}^{\alpha}(x)} \cdot {P_{B}^{\beta}(x)}} \right. & (18)\end{matrix}$

In this way, the potential function synthesizing unit 53, whenconverting the logical OR into a multiplication operator, sets thedegree of the priority of the atomic task to the exponent of thecorresponding atomic potential function. This allows the potentialfunction synthesizing unit 53 to weight each atomic potential functionin accordance with the priority and facilitate early execution of higherpriority atomic tasks.

When converting the logical expression “φ_(A)∧φ_(B)” corresponding tothe logical AND using the maximum value operator (see the expression(2)), the potential function synthesizing unit 53 multiplies each atomicpotential function by the degree of the priority of the correspondingatomic task, for example, as shown in the following expression (19).

$\begin{matrix}\left. {\varphi_{A} ⩓ \varphi_{B}}\Rightarrow{\max\left\{ {{\alpha \cdot {P_{A}(x)}},{\beta \cdot {P_{B}(x)}}} \right\}} \right. & (19)\end{matrix}$

This also allows the potential function synthesizing unit 53 to weighteach atomic potential function in accordance with the priority andfacilitate early execution of higher priority atomic tasks.

Similarly, when converting the logical expression “φ_(A) ∨φ_(B)”corresponding to the logical AND using the minimum value operator (seethe expression (4)), the potential function synthesizing unit 53multiplies each corresponding atomic potential function by the inverseof the degree of the priority of the corresponding atomic task, forexample, as shown in the expression (20) below.

φ ⁢ A ⋁ φ B ⇒ min ⁢ { 1 α ⁢ P A ( x ) , 1 β ⁢ P B ( x ) } ( 20 )

Even in this case, the potential function synthesizing unit 53 alsoperforms weighting corresponding to the priority for each atomicpotential function and prioritizes the execution of higher priorityatomic tasks.

The information processing device 1 may determine the degree of thepriority to be set for each atomic task based on the user input. FIG. 7is a display example of a task input view according to thismodification.

As shown in FIG. 7, the display control unit 50 displays priorityranking designation fields 64 for giving a priority ranking to eachatomic task on the task input view. Each of the priority rankingdesignation fields 64 is provided corresponding to each of the fouratomic tasks (the first atomic task to the fourth atomic task), andaccepts the designation of the priority ranking for the correspondingatomic task. In the example of FIG. 7, the ranking of the first atomictask “φ (A, C)” is the highest priority ranking (first ranking), and theranking of the second atomic task “φ (A, D)” is the lowest priorityranking (fourth ranking).

When the execution button 63 is selected, the potential functionsynthesizing unit 53 determines the degree of the priority of eachatomic task based on the priority ranking of each atomic task designatedin the corresponding priority specification field 64. In this case, thepotential function synthesizing unit 53 determines the degree of thepriority of each atomic task so that the higher the priority ranking is,the larger the degree of the priority becomes, based on predeterminedrules or by referring to a predetermined table and the like.

In this way, according to the task input view shown in FIG. 7, thepriority ranking of each atomic task to be used can be suitablyspecified by the user. Instead of the priority ranking designation field64, the display control unit 50 may display an input field of the degreeof the priority for each atomic task on the task input view and acceptthe specification of the degree of the priority of each atomic task.

Second Modification

In the second conversion process, the potential function synthesizingunit 53 may associate the logical AND with the average value of thetasks, instead of simply replacing the logical AND with the additionoperator as shown in the expression (1).

For example, the potential function synthesizing unit 53 may convert thelogical AND “φ_(A)∧φ_(B)∧φ_(C)” of the proposition “φ_(A)” of the atomictask A, the proposition “φ_(B)” of the atomic task B, and theproposition “φ_(C)” of the atomic task C according to the followingexpression (21).

φ ⁢ A ⋀ φ B ⋀ φ C ⇒ 1 3 ⁢ ( P A ( x ) + P B ( x ) + P C ( x ) ) ( 21 )

In this case, the potential function synthesizing unit 53 determines thelogical AND to be the average of the atomic tasks and calculates theaverage value of the corresponding atomic potential functions. Thepotential function synthesizing unit 53 similarly calculates the averagevalue of the corresponding atomic potential functions for the logicalAND of two or more than three atomic propositions.

Similarly, the potential function synthesizing unit 53 may convert thelogical OR “φ_(A)∨φ_(B)∨φ_(C)” according to the following expression(22).

φ ⁢ A ⋁ φ B ⋁ φ C ⇒ ( P A ( x ) · P B ( x ) · P C ( x ) ) 1 3 ( 22 )

In this case, the potential function synthesizing unit 53 determines thelogical OR to be the geometric average of the atomic tasks andcalculates the geometric average of the corresponding atomic potentialfunctions. The potential function synthesizing unit 53 similarlycalculates the geometric average of the corresponding atomic potentialfunctions for the logical OR of two or more than three atomicpropositions.

Even when the conversions of the logical AND the logical OR areperformed in this way, the information processing device 1 can suitablyderive the objective function that defines the operation of each of therobots 6 from the task logical expression specified by the user.

Third Modification

Examples of robot models in which the artificial potential field methodcan be used are not limited to the robot model in which the derivative(i.e., velocity) of the position is used as the control input, as shownin the expressions (13) and (14). Alternatively, for example, it may bea robot model in which the acceleration is used as the control input.The detail of the example of the above-mentioned robot model isdescribed in Non-Patent Literature 1, for example.

Fourth Modification

Instead of transmitting the control signal S3 indicating the objectivefunction to each of the robots 6, the information processing device 1may transmit a control signal S3 indicating the control input determinedfrom the objective function to each of the robots 6.

FIG. 8 is an example of a functional block of an information processingdevice 1A that transmits a control signal S3 indicating a control input.The processor 11 of the information processing device 1 shown in FIG. 8includes a control input determination unit 55. The control inputdetermination unit 55 determines the control input to be inputted toeach of the robots 6, based on the objective function outputted by theobjective function output unit 54 and the position information regardingeach of the robots 6 and the like. Then, the control input determinationunit 55 transmits the control signal S3 indicating the control input toeach of the robots 6 via the communication device 5. In this case, forexample, the control input determining unit 55 receives the positioninformation or the like regarding each of the robots 6 from each of therobots 6 via the communication device 5. In another example, the controlinput determination unit 55 is electrically connected to sensors such asa camera and a range measurement sensor and measures or estimates theposition and the like regarding each of the robots 6, based on thedetection signal outputted by the sensors.

In this way, even in such a mode that the information processing device1 determines the control input to be inputted to each of the robots 6and transmits the control signal S3 indicative of the control input toeach of the robots 6, the information processing device 1 can suitablymake each of the robots 6 perform the objective task.

Fifth Modification

Each of the robot 6 may have one or more functions which the informationprocessing device 1 has instead.

For example, the information processing device 1 may transmit thecontrol signal S3 indicating the task logical expression to each of therobots 6, and each of the robots 6 may generate an objective functionbased on the task logical expression specified by the control signal S3and autonomously move based on the objective function. In this case,each of the robots 6 are configured to be capable of storing orreferring to the atomic task DB 41, and have functions corresponding tothe acquisition unit 51, the potential function synthesizing unit 53,and the objective function output unit 54 which are shown in thefunctional block in FIG. 4. In this case, each of the robots 6 acquiresthe control signal S3 indicating the task logical expression from theinformation processing device 1. Then, as with the potential functionsynthesizing unit 53, each of the robots 6 refers to the atomic task DB41 and executes the first conversion process and the second conversionprocess described above for the specified task logical expression tothereby synthesize the atomic potential functions. Then, as with theobjective function output unit 54, each of the robots 6 outputs thesynthesized atomic potential function as an objective function toanother functional block in the robot 6 for calculating an artificialforce field based on the artificial potential field method.

Sixth Modification

The process performed by the atomic task setting unit 52 described inFIG. 4 may be performed by a device other than the informationprocessing device 1. In this case, the above-described device can referto and update the atomic task DB 41, and update the atomic task DB 41based on the user input of the input device 2 or other input device.

Seventh Modification

Only one robot 6 may be the execution subject (i.e., the control target)of the objective task although a plurality of robots 6 are the executionsubjects of the objective task in the configuration example of the robotcontrol system 100 illustrated in FIG. 1. Even in this case, theinformation processing device 1 can receive the input of the tasklogical expression which expresses the complex objective task for onerobot 6 by the combination of the atomic tasks, and appropriately outputthe corresponding objective function.

Second Example Embodiment

FIG. 9 is a functional block diagram of the information processingdevice 1B according to the second example embodiment. As shown in FIG.9, the information processing device 1B mainly includes an acquisitionunit 51A, a potential function synthesizing unit 53A, and an objectivefunction output unit 54A.

The acquisition unit 51A acquires a task logical expression in which anobjective task to be performed by a robot is expressed by a combinationof a plurality of atomic tasks. The potential function synthesizing unit53A synthesizes (combines) atomic potential functions, each of which isa potential function corresponding to each of the atomic tasks, based onthe task logical expression. The objective function output unit 54Aoutputs an atomic potential function synthesized based on the tasklogical expression as an objective function for controlling the robot.

The information processing device 1B according to the second exampleembodiment outputs the objective function for controlling a robot bysynthesizing the atomic potential function corresponding to each ofatomic tasks when the task logical expression in which the objectivetask is indicated by the combination of the atomic tasks is acquired.Thereby, the information processing device 1B can easily design theobjective function according to the contents of the complicated work inthe control of the robot using the artificial potential field method.

The whole or a part of the example embodiments described above(including modifications, the same applies hereinafter) can be describedas, but not limited to, the following Supplementary Notes.

[Supplementary Note 1]

An information processing device comprising:

-   -   an acquisition unit configured to acquire a logical expression        in which an objective task to be performed by a robot is        expressed by a combination of a plurality of tasks;    -   a potential function synthesizing unit configured to synthesize        atomic potential functions, each of which is a potential        function corresponding to each of the tasks, based on the        logical expression; and    -   an objective function output unit configured to output a        potential function synthesized based on the logical expression        as an objective function for controlling the robot.

[Supplementary Note 2]

The information processing device according to Supplementary Note 1,

-   -   wherein the potential function synthesizing unit is configured        to determine the atomic potential functions to be synthesized by        referring to task information stored in a storage unit, the task        information associating each of the tasks with a corresponding        atomic potential function.

[Supplementary Note 3]

The information processing device according to Supplementary Note 1 or2,

-   -   wherein, when synthesizing the atomic potential functions based        on the logical expression, the potential function synthesizing        unit is configured to convert a logical connector included in        the logical expression to an arithmetic operator for performing        an operation of the atomic potential functions.

[Supplementary Note 4]

The information processing device according to Supplementary Note 3,

-   -   wherein, when converting the logical connector to the arithmetic        operator, the potential function synthesizing unit is configured        to convert a logical conjunction to an addition operator or a        maximum value operator and convert a logical disjunction to a        multiplication operator or a minimum value operator.

[Supplementary Note 5]

The information processing device according to any one of SupplementaryNotes 1 to 4,

-   -   wherein the objective task is performed by a plurality of robots        jointly, and    -   wherein each of the tasks is to be performed by one of the        robots.

[Supplementary Note 6]

The information processing device according to any one of SupplementaryNotes 1 to 5,

-   -   wherein the acquisition unit is configured to acquire the        logical expression by at least accepting an input which        specifies a proposition corresponding to each of the tasks and a        logical connector for the proposition.

[Supplementary Note 7]

The information processing device according to any one of SupplementaryNotes 1 to 6, further comprising

-   -   a display control unit configured to display a symbol indicative        of a proposition corresponding to each of the tasks and        explanation of the each of the tasks indicated by the symbol,    -   wherein the acquisition unit is configured to acquire the        logical expression by at least accepting an input which        specifies the symbol indicative of the proposition corresponding        to each of the tasks and a logical connector for the        proposition.

[Supplementary Note 8]

The information processing device according to any one of SupplementaryNotes 1 to 7,

-   -   wherein the acquisition unit is configured to further acquire a        priority of each of the tasks, and    -   wherein the potential function synthesizing unit is configured        to synthesize the atomic potential functions based on the        logical expression and the priority.

[Supplementary Note 9]

The information processing device according to Supplementary Note 8,

-   -   wherein, when converting a logical conjunction between a first        task and a second task included in the tasks to an addition        operator, the potential function synthesizing unit is configured        to multiply an atomic potential function corresponding to the        first task by the priority of the first task and multiply an        atomic potential function corresponding to the second task by        the priority of the second task.

[Supplementary Note 10]

The information processing device according to Supplementary Note 8,

-   -   wherein, when converting a logical disjunction between a first        task and a second task included in the tasks to a multiplication        operator, the potential function synthesizing unit is configured        to set the priority of the first task as an exponent of an        atomic potential function corresponding to the first task and        set the priority of the second task as an exponent of an atomic        potential function corresponding to the second task.

[Supplementary Note 11]

The information processing device according to Supplementary Note 1 or2,

-   -   wherein, provided that atomic potential functions corresponding        to any two of the tasks are denoted by “P_(A)(x)” and        “P_(B)(x)”, respectively, the potential function synthesizing        unit is configured to convert, by use of a parameter “p”, a        logical conjunction between the two of the tasks and a logical        disjunction between the two of the tasks to

$\begin{matrix}0 & \left( {p < {0\bigwedge\left( {{P_{A}(x)} = {{0\bigvee{P_{B}(x)}} = 0}} \right)}} \right. \\\left( {{P_{A}^{p}(x)} + {P_{B}^{p}(x)}} \right)^{\frac{1}{p}} & {OTHER}\end{matrix},$

-   -   wherein the parameter is set to “p>0” in case of conversion of        the logical conjunction and the parameter is set to “p<0” in        case of conversion of the logical disjunction.

[Supplementary Note 12]

A control method executed by an information processing device, thecontrol method comprising:

-   -   acquiring a logical expression in which an objective task to be        performed by a robot is expressed by a combination of a        plurality of tasks;    -   synthesizing atomic potential functions, each of which is a        potential function corresponding to each of the tasks, based on        the logical expression; and    -   outputting a potential function synthesized based on the logical        expression as an objective function for controlling the robot.

[Supplementary Note 13]

A storage medium storing a program executed by a computer, the programcausing the computer to function as:

-   -   an acquisition unit configured to acquire a logical expression        in which an objective task to be performed by a robot is        expressed by a combination of a plurality of tasks;    -   a potential function synthesizing unit configured to synthesize        atomic potential functions, each of which is a potential        function corresponding to each of the tasks, based on the        logical expression; and    -   an objective function output unit configured to output a        potential function synthesized based on the logical expression        as an objective function for controlling the robot.

While the invention has been particularly shown and described withreference to example embodiments thereof, the invention is not limitedto these embodiments. It will be understood by those of ordinary skilledin the art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present invention asdefined by the claims. In other words, it is needless to say that thepresent invention includes various modifications that could be made by aperson skilled in the art according to the entire disclosure includingthe scope of the claims, and the technical philosophy. All Patent andNon-Patent Literatures mentioned in this specification are incorporatedby reference in its entirety.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1, 1A, 1B Information processing device    -   2 Input device    -   3 Display device    -   4 Storage device    -   5 Communication device    -   6, 6A, 6B robots    -   41 Atomic task DB    -   100 Robot control system

What is claimed is:
 1. An information processing device comprising amemory configured to store a program and a processor configured toexecute the program to: acquire a logical expression in which anobjective task to be performed by a robot is expressed by a combinationof a plurality of tasks; synthesize atomic potential functions, each ofwhich is a potential function corresponding to each of the tasks, basedon the logical expression; and output a potential function synthesizedbased on the logical expression as an objective function for controllingthe robot.
 2. The information processing device according to claim 1,wherein the processor is configured to determine the atomic potentialfunctions to be synthesized by referring to task information stored in astorage unit, the task information associating each of the tasks with acorresponding atomic potential function.
 3. The information processingdevice according to claim 1, wherein, when synthesizing the atomicpotential functions based on the logical expression, the processor isconfigured to convert a logical connector included in the logicalexpression to an arithmetic operator for performing an operation of theatomic potential functions.
 4. The information processing deviceaccording to claim 3, wherein, when converting the logical connector tothe arithmetic operator, the processor is configured to convert alogical conjunction to an addition operator or a maximum value operatorand convert a logical disjunction to a multiplication operator or aminimum value operator.
 5. The information processing device accordingto claim 1, wherein the objective task is performed by a plurality ofrobots jointly, and wherein each of the tasks is to be performed by oneof the robots.
 6. The information processing device according to claim1, wherein the processor is configured to acquire the logical expressionby at least accepting an input which specifies a propositioncorresponding to each of the tasks and a logical connector for theproposition.
 7. The information processing device according to claim 1,wherein the processor is further configured to display a symbolindicative of a proposition corresponding to each of the tasks andexplanation of the each of the tasks indicated by the symbol, whereinthe processor is configured to acquire the logical expression by atleast accepting an input which specifies the symbol indicative of theproposition corresponding to each of the tasks and a logical connectorfor the proposition.
 8. The information processing device according toclaim 1, wherein the processor is configured to further acquire apriority of each of the tasks, and wherein the processor is configuredto synthesize the atomic potential functions based on the logicalexpression and the priority.
 9. The information processing deviceaccording to claim 8, wherein, when converting a logical conjunctionbetween a first task and a second task included in the tasks to anaddition operator, the processor is configured to multiply an atomicpotential function corresponding to the first task by the priority ofthe first task and multiply an atomic potential function correspondingto the second task by the priority of the second task.
 10. Theinformation processing device according to claim 8, wherein, whenconverting a logical disjunction between a first task and a second taskincluded in the tasks to a multiplication operator, the processor isconfigured to set the priority of the first task as an exponent of anatomic potential function corresponding to the first task and set thepriority of the second task as an exponent of an atomic potentialfunction corresponding to the second task.
 11. The informationprocessing device according to claim 1, wherein, provided that atomicpotential functions corresponding to any two of the tasks are denoted by“P_(A)(x)” and “P_(B)(x)”, respectively, the processor is configured toconvert, by use of a parameter “p”, a logical conjunction between thetwo of the tasks and a logical disjunction between the two of the tasksto $\begin{matrix}0 & \left( {p < {0\bigwedge\left( {{P_{A}(x)} = {{0\bigvee{P_{B}(x)}} = 0}} \right)}} \right. \\\left( {{P_{A}^{p}(x)} + {P_{B}^{p}(x)}} \right)^{\frac{1}{p}} & {OTHER}\end{matrix},$ wherein the parameter is set to “p>0” in case ofconversion of the logical conjunction and the parameter is set to “p<0”in case of conversion of the logical disjunction.
 12. A control methodexecuted by an information processing device, the control methodcomprising: acquiring a logical expression in which an objective task tobe performed by a robot is expressed by a combination of a plurality oftasks; synthesizing atomic potential functions, each of which is apotential function corresponding to each of the tasks, based on thelogical expression; and outputting a potential function synthesizedbased on the logical expression as an objective function for controllingthe robot.
 13. A non-transitory computer readable storage medium storinga program executed by a computer, the program causing the computer to:acquire a logical expression in which an objective task to be performedby a robot is expressed by a combination of a plurality of tasks;synthesize atomic potential functions, each of which is a potentialfunction corresponding to each of the tasks, based on the logicalexpression; and output a potential function synthesized based on thelogical expression as an objective function for controlling the robot.